DuPont acetate copolymers

Slow release preparations Recombinant growth factors are prepared as slow-release pellets by incorporating the test molecule into an ethylene-vinyl-acetate copolymer (Elvax-40) (DuPont de... 

Elvax Ethylene-vinyl Acetate Copolymer Resins, Data Sheets and Other Technical Literature, DuPont Paekaging, E. I. DuPont de Nemours and Company. 

Most hot-melts are based on polyolefins. The best known hot-melt is ethylene-vinyl acetate copolymer (EVA), e.g., duPont Elvax. In 1983, duPont added a new line of resins... 

Alathon Ethylene/vinyl acetate copolymer. Manufactured by DuPont, USA. 

The Asahi Kasai Corporation (50%) and DuPont China Holding Company (50%) joint venture produces acetal copolymer at Zhangjiagang, Jiangsu Province, People s Republic of China, to sell jointly in China and separately outside China. Mitsubishi Gas Company produces acetal copolymer in south Korea, Japan, and Thailand. PTM Engineering... 

In 1946, DuPont scientists reported ethylene/vinyl acetate copolymers [7], which were not commercialized until 1961. However, this work provided the wide range of ethylene/vinyl copolymers that have become the driving force behind the continued growth of the high-pressure process today, as these materials are unique to the high-pressure process. 

Ethylene-Vinyl Acetate Copolymers E.I. duPont de Nemours Co., Inc. 

Low-density polyethylene was utilized as the control (LF-0219-A Novapol). The ethylene-vinyl acetate copolymers varied in vinyl acetate content from 9.3, 18, 28, to 40% (Elvax 760Q, 460, 265, and 40L-03, respectively DuPont). The organomontmorillonites that were evaluated were Cloisite 20A, Cloisite 30B, and montmorillonite exchanged with trimethyl hydrogenated tallow quaternary ammonium ion at the exchange capacity of the montmorillonite. 

Elvax 265, 40L03 Ethylene/vinyl acetate copolymer DuPont Company... 

Polyacetals prepared from formaldehyde are engineering thermoplastics, which have found use in traditional metal applications. Some trade names of these polymers are Delrin acetal homopolymer (DuPont) Celcon acetal copolymer (Celanese/Hoechst) Duracon acetal copolymer (Celanese and Diacel—joint venture) Tenac acetal homopolymer by Asahi Chemical in Japan and Ultraform acetal copolymer jointly by BASF and Degussa, in Germany. The polymers have the basic structure shown below ... 

Uses Emulsifier for vinyl acetate copolymers, S/B latexes, vinyl chloride copolymers, acrylate homo- and copolymers Properties Liq. 27-30% solids Avltone A [DuPont DuPont Canada]... 

Ticona. The Celcon acetal copolymer design manual, 2006. Dehin Design infmmation, module III, DuPont publ No. 1 10464, 2006. 

Material suppliers have also been working to address this issue. DuPont recently began manufacturing a low-emission acetal resin [17], Celanese, another material supplier, has also developed a low-emission acetal copolymer called Hostaform XAP, that also meets original equipment manufacturer (OEM) performance requirements for low-VOC emissions. As technologies continue to develop, that familiar new car smell will gradually transform into a new ideal no car smell. Known as vehicle interior air quality (VIAQ), this is an important field requiring further research. 

Poly(vinyl chloride) (PVC) wall covering Cellulose acetate sheet and rods Graft copolymers Nylon (Carothers DuPont)... 

Acetal translucent crystalline polymer is one of the stiffest TPs available. It provides excellent hardness and heat resistance, even in the presence of solvents and alkalies. Its low moisture sensitivity and good electrical properties permit direct competition with die-cast metal in a variety of applications. In addition, acetal has extremely high creep resistance and low permeability. Acetal is also available as a copolymer (Hoechst Celanese Corp. s Celcon) for improved processability. The homopolymer (DuPont s Delrin) has a very low coefficient of friction and its resistance to abrasion is second only to nylon 6/6. Acetals are frequently blended with fibers such as glass or fluorocarbon to enhance stiffness and friction properties. Acetal is not particularly weather-resistant, but grades are available with UV stabilizers for improved outdoor performance. Acetal, whether homopolymer or copolymer, is not used to any significant degree in forming structural foams. 

The industrial process for the vapor-phase manufacture of vinyl acetate monomer is quite common (Daniels, 1989) and utilizes widely available raw materials. Vinyl acetate is used chiefly as a monomer to make polyvinyl acetate and other copolymers. Hoechst-Celanese, Union Carbide, and Quantum Chemical are reported U.S. manufacturers. DuPont also currently operates a vinyl acetate process at its plant in LaPorte, Texas. To protect any proprietary DuPont information, all of the physical property and kinetic data, process flowsheet information, and modeling formulation in the published paper come from sources... 

Certain copolymers of ethylene and vinyl acetate, poly[ethylene-co-(vinyl acetate)] (EVAc, ELVAX , Dupont Corp.), have exceptionally good biocompatibility and are therefore widely used in implanted and topical devices. 

The copolymer is synthesized by free-radical polymerization from ethylene and vinyl acetate. The most commonly used EVAc (ELVAX-40, DuPont) consists of 40% vinyl acetate, with a low degree of crystallinity (5-20%). EVAc is hydrophobic it swells less than 0.8% in water [28]. 

The useful vinyl acetate-ethylene copolymers are milk-white dispersions of 55 w/o solids in water with a viscosity between 12 and 45 poises. DuPont s Elvace is a commercially available dispersion with these characteristics. 

There are two basic types of acetals. DuPont produces the homopolymers whereas Celanese produces the copolymers. 

General Description Ethylene Vinyl Acetate (EVA) Copolymer is a copolymer resin ranging in vinyl acetate content from 7.5 wt% to 33 wt%. DuPont Elvax and Equistar Ultrathene grades vary by vinyl acetate content. Some grades are available with antiblock and slip additives. The vinyl acetate units in the copolymer modify the basic polyethylene structure and its properties. The addition of vinyl acetate to polyethylene provides lower sealing temperature, increased flexibility, improved optical properties, greater adhesion, increased impact, and puncture resistance. 

DuPont, in the late fifties, introduced ethylene vinyl acetate (EVA) copolymers as specialty low-crystallinity copolymers. EVA copolymers are produced by introducing vinyl acetate comonomer in the high-pressure process. 

Acetal polymers are formed from the polymerization of formaldehyde. They are also given the name polyoxymethylenes (POMs). Polymers prepared from formaldehyde were studied by Staudinger in the 1920s, but thermally stable materials were not introduced until the 1950s, when DuPont developed Dehin. Hompolymers are prepared from very pure formaldehyde by anionic polymerization as shown in Fig. 2.1. Amines and the soluble salts of alkali metals catalyze the reaction. The polymer formed is insoluble and is removed as the reaction proceeds. Thermal degradation of the acetal resin occurs by unzipping with the release of formaldehyde. The thermal stability of the polymer is increased by esterification of the hydroxyl ends with acetic anhydride. An alternative method to improve the thermal stabihty is copolymerization with a second monomer, such as ethylene oxide. The copolymer is prepared by cationic methods developed by Celanese and mar-... 

Acetals are produced by Asahi Chemical (homopolymer Tenac, copolymer Tenac-C, and conductive copolymer Lynex-T ), BASF (copolymer Ultraform ), DuPont (homopolymer Delrin ), Mitsubishi Gas Chemical (copolymer lupital ). Polyplastics (copolymer Duracon in Asia) and a joint venture between Ticona and Daicel Chemical Industries, Ticona/Celanese AG (copolymer Celcon and Hostaform in Europe). Mitsubishi Gas Chemical, Polyplastics, and Ticona are (jointly, directly, or through affiliates) increasing acetal production capacity in the Asia/Pacific area, with a new 60,(XX) metric ton/year plant to be completed in 2004 in Nantong, Jiangsu province, north of Shanghai. ... 

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